RU2825658C2 - Method of producing nanodiamonds doped with element of group 14, and method for purifying thereof - Google Patents

Abstract

FIELD: nanotechnology.

SUBSTANCE: invention relates to nanotechnology and can be used in making probes for fluorescence imaging, as well as in optically detected magnetic resonance. Method of producing nanodiamond doped with an element of group 14 includes alkaline treatment of a nanodiamond composition containing at least one element of this group, and nanodiamond doped with an element of this group, with removal of an element of group 14 and its oxide, where said element is selected from Si, Ge, Sn and Pb. This composition is obtained by detonation in a sealed container of an explosive composition containing at least one explosive and at least one compound of said element of group 14. Explosive composition can additionally contain a compound containing at least one third element selected from B, P, S, Cr, Al, Li, Na, K, Cs, Mg, Ca, Sr, Ba, Ti, Zr, V, Nb, Ta, Mo, W, Mn, Fe, Ni, Cu, Ag, Zn, Cd, Hg, Ga, In, Tl, As, Sb, Bi, Se, Te, Co, Xe, F, Y and lanthanides. Nanodiamond doped with an element of group 14 and said third element can be additionally treated with a mixed acid consisting of concentrated nitric and sulfuric acids before or after alkaline treatment.

EFFECT: invention enables to obtain nanodiamonds doped with said elements and purification thereof.

6 cl, 2 dwg, 3 tbl, 9 ex

Description

Field of technology

[0001]

The present invention relates to a method for producing nanodiamonds doped with a group 14 element, as well as to a method for purifying them.

State of the art

[0002]

The luminescence center in diamond is a nanoscale chemically stable fluorescent chromophore that does not exhibit degradation, decay or blinking in vivo , which often occurs in organic fluorescence, and is therefore expected to be used as probes for fluorescence imaging. In addition, the spin information of the electrons excited in the luminescence center can sometimes be measured externally, and is therefore expected to be used in optically detected magnetic resonance (ODMR) or as a quantum bit.

[0003]

The silicon vacancy center (Si-V), which is a type of diamond luminescence center, has a sharp peak called the zero-phonon level (ZPL) in the emission spectrum (Non-patent Literature 1).

[0004]

Silicon-doped diamonds are produced by CVD (chemical vapor deposition) method, for example (Patent Documents 1 and 2).

[0005]

Non-patent literature 2 analyzes nanodiamonds in meteorite; however, the fabrication of nanodiamonds having a silicon vacancy (SiV) center is not described. Non-patent literature 2 describes that the Si-V center in nanodiamond with a size of 1.1 nm to 1.8 nm is thermodynamically stable according to modeling.

[0006]

Figure 1 of Non-Patent Literature 3 shows nanodiamonds with Si-V center corrected by CVD (chemical vapor deposition) method according to AFM (atomic microscopy). In the graph in the upper right part of Figure 1, the vertical axis represents the height (nm), and the horizontal axis represents the position (µ), and it is obvious that its peak height is about 9 nm, and the width (position) is at least 70 nm.

[0007]

In non-patent literature 4, it is described that by using nanodiamonds with a size of 3 to 4 nm as a seed solution and growing on a silicon substrate using the MWPE-CVD (microwave plasma-enhanced plasma chemical vapor deposition) method, nanodiamonds with an average particle diameter of 73 nm and a SiV center can be obtained.

List of contrasting materials

Patent document

[0008]

Patent Document 1: JP 2014-504254 T

Patent Document 2: JP 2004-176132 A

Non-patent literature

[0009]

Non-patent literature 1: E. Neu et al. APPLIED PHYSICS LETTERS 98, 243107 (2011)

Non-Patent Literature 2: Nat Nanotechnol. 2014 Jan; 9(1): 54-8. doi: 10.1038/nnano.2013.255. Epub 2013 Dec 8.

Non-Patent Literature 3: Adv Sci Lett. 2011 Feb 1; 4(2): 512-515.

Non-Patent Literature 4: Diamond and Related Materials, Volume 65, 2016, Pages 87-90

The essence of the invention

Technical task

[0010]

The aim of the present invention is to provide a method for producing nanodiamonds doped with group 14 elements such as silicon (Si), germanium (Ge) and tin (Sn), as well as a method for purifying them.

Solving a technical problem

[0011]

The present invention provides a method for producing nanodiamonds doped with group 14 elements and a method for purifying them, as described below.

Item 1. A method for producing a nanodiamond doped with an element of group 14, comprising:

detonating by explosion an explosive composition containing at least one explosive substance and at least one compound of a group 14 element in a sealed container to produce a nanodiamond doped with at least one group 14 element selected from the group consisting of Si, Ge, Sn and Pb, and

alkaline treatment of nanodiamond doped with a group 14 element, with the removal of the group 14 element and/or its oxide.

Item 2. A method for producing a nanodiamond doped with a group 14 element in accordance with item 1, further comprising treating the nanodiamond doped with a group 14 element with a mixed acid consisting of concentrated nitric acid and concentrated sulfuric acid, before or after alkaline treatment.

Item 3. A method for producing a nanodiamond doped with an element of group 14 according to item 1 or 2, wherein the explosive composition additionally comprises a compound containing at least one third element selected from the group consisting of B, P, S, Cr, Al, Li, Na, K, Cs, Mg, Ca, Sr, Ba, Ti, Zr, V, Nb, Ta, Mo, W, Mn, Fe, Ni, Cu, Ag, Zn, Cd, Hg, Ga, In, Tl, As, Sb, Bi, Se, Te, Co, Xe, F, Y and lanthanides.

Item 4. A method for purifying nanodiamond doped with an element of group 14, comprising:

alkaline treatment of a nanodiamond composition containing at least one group 14 element selected from the group consisting of Si, Ge, Sn and Pb and/or their oxide, and a nanodiamond doped with a group 14 element, with the removal of the group 14 element and/or its oxide.

Item 5. A method for purifying nanodiamond doped with an element of group 14 in accordance with item 4, wherein the nanodiamond composition is obtained by treatment with a mixed acid.

Item 6. A method for purifying a nanodiamond doped with an element of group 14 according to item 4 or 5, wherein the nanodiamond composition additionally contains at least one third element selected from the group consisting of B, P, S, Cr, Al, Li, Na, K, Cs, Mg, Ca, Sr, Ba, Ti, Zr, V, Nb, Ta, Mo, W, Mn, Fe, Ni, Cu, Ag, Zn, Cd, Hg, Ga, In, Tl, As, Sb, Bi, Se, Te, Co, Xe, F, Y and lanthanides, and/or its oxide.

Item 7. A method for purifying a nanodiamond doped with an element of group 14 according to any of items 4-6, wherein the nanodiamond is additionally doped with at least one third element selected from the group consisting of B, P, S, Cr, Al, Li, Na, K, Cs, Mg, Ca, Sr, Ba, Ti, Zr, V, Nb, Ta, Mo, W, Mn, Fe, Ni, Cu, Ag, Zn, Cd, Hg, Ga, In, Tl, As, Sb, Bi, Se, Te, Co, Xe, F, Y and lanthanides.

Positive effects of the invention

[0012]

Although at least one Group 14 element selected from the group consisting of Si, Ge, Sn and Pb and oxides thereof cannot be easily removed by mixed acid treatment, its removal from Group 14 element-doped nanodiamonds can be accomplished by alkali treatment.

Brief description of the drawings

[0013]

Fig. 1(a) shows the luminance image of silicon-doped nanodiamonds at a wavelength of 738 nm obtained using triphenylsilanol as the silicon compound in an added amount relative to the outer part, 1% by weight. Fig. 1(b) shows the fluorescence luminance spectrum. In Fig. 1(b), a side band (shoulder peak) of fluorescence is present at a wavelength of about 750 nm; however, depending on the sample, this side band may be absent.

Fig.2 shows the result of XRD measurement before and after alkali treatment. A: after alkali treatment, B: before alkali treatment.

Description of embodiments

[0014]

The nanodiamond, according to an embodiment of the present invention, may be, in addition to the element of group 14, additionally doped with another element. Examples of such an element include at least one element selected from the group consisting of B, P, S, Cr, Al, Li, Na, K, Cs, Mg, Ca, Sr, Ba, Ti, Zr, V, Nb, Ta, Mo, W, Mn, Fe, Ni, Cu, Ag, Zn, Cd, Hg, Ga, In, Tl, As, Sb, Bi, Se, Te, Co, Xe, F, Y and lanthanides (hereinafter, also referred to as the “third element”). In the case where the nanodiamond is doped with the third element, the explosive composition contains at least one explosive substance, at least one compound of the element of group 14 and, additionally, at least one compound of the third element.

[0015]

In the present description, a nanodiamond doped with a group 14 element and, if necessary, a third element, may be referred to simply as a “doped nanodiamond”.

[0016]

In an embodiment of the present invention, a manufacturing method according to an embodiment of the present invention comprises detonating by explosion an explosive composition containing at least one explosive substance and at least one compound of a group 14 element and, if necessary, at least one third element, in a sealed container to obtain nanodiamonds doped with group 14 elements and, if necessary, a third element, and also alkaline processing of the nanodiamonds doped with a group 14 element and, if necessary, a third element, with the removal of the group 14 element and/or its oxide.

[0017]

The group 14 element used for doping the nanodiamonds is at least one selected from the group consisting of Si, Ge, Sn and Pb, and is preferably Si.

[0018]

The explosive is not particularly limited, and known explosives can be widely used. Specific examples thereof include trinitrotoluene (TNT), cyclotrimethylenetrinitramine (RDX), cyclotetramethylenetetranitramine (HMX), trinitrophenylmethylnitramine (tetryl), pentaerythritol tetranitrate (PETN), tetranitromethane (TNM), triaminotrinitrobenzene, hexanitrostilbene, and diaminodinitrobenzofuroxan. These explosives can be used singly or in combination of two or more of these substances.

[0019]

The compound of a group 14 element comprises at least one element selected from the group consisting of silicon compounds, germanium compounds, tin compounds and lead compounds.

[0020]

Examples of organosilicon compounds include the following:

a silane having a lower alkyl group, such as acetoxytrimethylsilane, diacetoxydimethylsilane, triacetoxymethylsilane, acetoxytriethylsilane, diacetoxydiethylsilane, triacetoxyethylsilane, acetoxytripropylsilane, methoxytrimethylsilane, dimethoxydimethylsilane, trimethoxymethylsilane, ethoxytrimethylsilane, diethoxydimethylsilane, triethoxymethylsilane, ethoxytriethylsilane, diethoxydiethylsilane, triethoxyethylsilane and trimethylphenoxysilane;

[0021]

a silane having a halogen atom such as trichloromethylsilane, dichlorodimethylsilane, chlorotrimethylsilane, trichloroethylsilane, dichlorodiethylsilane, chlorotriethylsilane, trichlorophenylsilane, dichlorodiphenylsilane, chlorotriphenylsilane, dichlorodiphenylsilane, dichloromethylphenylsilane, dichloroethylphenylsilane, chlorodifluoromethylsilane, dichlorofluoromethylsilane, chlorofluorodimethylsilane, chloroethyldifluorosilane, dichloroethylfluorosilane, chlorodifluoropropylsilane, dichlorofluoropropylsilane, trifluoromethylsilane, difluorodimethylsilane, fluorotrimethylsilane, ethyltrifluorosilane, diethyldifluorosilane, triethylfluorosilane, trifluoropropylsilane, fluorotripropylsilane, trifluorophenylsilane, difluorodiphenylsilane, fluorotriphenylsilane, tribromomethylsilane, dibromodimethylsilane, bromotrimethylsilane, bromotriethylsilane, bromotripropylsilane, dibromodiphenylsilane and bromotriphenylsilane;

[0022]

polysilane such as hexamethyldisilane, hexaethyldisilane, hexapropyldisilane, hexaphenyldisilane and octaphenylcyclotetrasilane;

silazane such as triethylsilazane, tripropylsilazane, triphenylsilazane, hexamethyldisilazane, hexaethyldisilazane, hexaphenyldisilazane, hexamethylcyclotrisilazane, octamethylcyclotetrasilazane, hexaethylcyclotetrasilazane, octaethylcyclotetrasilazane and hexaphenylcyclotrisilazane;

an aromatic silane in which a silicon atom is incorporated into an aromatic ring, such as silabenzene and disilabenzene;

a hydroxy group-containing silane such as trimethylsilanol, dimethylphenylsilanol, triethylsilanol, diethylsilanediol, tripropylsilanol, dipropylsilanediol, triphenylsilanol and diphenylsilanediol;

[0023]

an alkyl or aryl substituted silane such as tetramethylsilane, ethyltrimethylsilane, trimethylpropylsilane, trimethylphenylsilane, diethyldimethylsilane, triethylmethylsilane, methyltriphenylsilane, tetraethylsilane, triethylphenylsilane, diethyldiphenylsilane, ethyltriphenylsilane and tetraphenylsilane;

a silane containing a carboxyl group such as triphenylsilylcarboxylic acid, trimethylsilylacetic acid, trimethylsilylpropionic acid and trimethylsilylbutyric acid;

[0024]

siloxane such as hexamethyldisiloxane, hexaethyldisiloxane, hexapropyldisiloxane and hexaphenyldisiloxane;

a silane having an alkyl group or an aryl group and a hydrogen atom, such as methylsilane, dimethylsilane, trimethylsilane, diethylsilane, triethylsilane, tripropylsilane, diphenylsilane and triphenylsilane; and

tetrakis(chloromethyl)silane, tetrakis(hydroxymethyl)silane, tetrakis(trimethylsilyl)silane, tetrakis(trimethylsilyl)methane, tetrakis(dimethylsilanolyl)silane, tetrakis(tri(hydroxymethyl)silyl)silane, and tetrakis(nitratemethyl)silane.

[0025]

Examples of inorganic silicon compound include silicon oxide, silicon oxynitride, silicon nitride, silicon oxycarbide, silicon nitrocarbide, silane, and silicon-doped carbon materials. Examples of silicon-doped carbon material include black lead, graphite, active carbon, carbon black, ketene black, coke, soft carbon, hard carbon, acetylene black, carbon fibers, and mesoporous carbon.

[0026]

A single organic or inorganic silicon compound may be used alone, or two or more organic or inorganic silicon compounds may be used in combination.

[0027]

Examples of the germanium compound include organic germanium compounds such as methylgermane, ethylgermane, trimethylgermanium methoxide, dimethylgermanium diacetate, tributylgermanium acetate, tetramethoxygermanium, tetraethoxygermanium, isobutylgermane, alkylgermanium trichloride and dimethylaminogermanium trichloride, germanium complexes such as nitrotriphenol complex ( _Ge2 (ntp) _2O ), catechol complex (Ge(cat) ₂ ) or aminopyrene complex ( _Ge2 (ap) _{2Cl2 )} and germanium alkoxide such as germanium ethoxide and germanium tetrabutoxide.

[0028]

One germanium compound may be used alone, or two or more germanium compounds may be used in combination.

[0029]

Examples of the tin compound include inorganic tin compounds such as tin(II) oxide, tin(IV) oxide, tin(II) sulfide, tin(IV) sulfide, tin(II) chloride, tin(IV) chloride, tin(II) bromide, tin(II) fluoride, tin acetate and tin sulfate, alkyl tin compounds such as tetramethyltin, monoalkyl tin oxide compounds such as monobutyltin oxide, dialkyl tin oxide compounds such as dibutyltin oxide, aryl tin compounds such as tetraphenyltin, and organic tin compounds such as dimethyltin maleate, hydroxybutyltin oxide and tris(2-ethylhexanoate)monobutyltin.

[0030]

One tin compound may be used alone, or two or more tin compounds may be used in combination.

[0031]

Examples of lead compound include inorganic lead compounds such as lead monoxide (PbO), lead dioxide (PbO ₂ ), lead ortholead (Pb ₃ O ₄ ), basic lead carbonate (2PbCO ₃ Pb(OH) ₂ ), lead nitrate (Pb(NO ₃ ) ₂ ), lead chloride (PbCl ₂ ), lead sulfide (PbS), chrome yellow (PbCrO ₄ , Pb(SCr)O ₄ , PbO PbCrO ₄ ), lead carbonate (PbCO ₃ ), lead sulfate (PbSO ₄ ), lead fluoride (PbF ₂ ), lead tetrafluoride (PbF ₄ ), lead bromide (PbBr ₂ ) and lead iodide (PbI ₂ ), as well as organic lead compounds such as lead acetate (Pb(CH ₃ COO) ₂ ), lead tetracarboxylate (Pb(OCOCH ₃ ) ₄ ), tetraethyl lead (Pb(CH ₃ CH ₂ ) ₄ ), tetramethyl lead (Pb(CH ₃ ) ₄ ) and tetrabutyl lead (Pb(C ₄ H ₉ ) ₄ ).

[0032]

One lead compound may be used alone, or two or more lead compounds may be used in combination.

[0033]

Examples of the compound of the third element include organic compounds of the third element and inorganic compounds of the third element, and one or a combination of two or more types of compounds of the third element may be used.

[0034]

An example of the third element connection is given below.

[0035]

Examples of boron compounds include inorganic boron compounds and organic boron compounds.

[0036]

Examples of inorganic boron compound include orthoboric acid, diboron dioxide, diboron trioxide, tetraboron trioxide, tetraboron pentoxide, boron tribromide, tetrafluoroboric acid, ammonium borate, and magnesium borate.

[0037]

Examples of the organoboron compound include triethylborane, (R)-5,5-diphenyl-2-methyl-3,4-propano-1,3,2-oxazaborolidine, triisopropyl borate, 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane, bis(hexyleneglycolato)diborone, 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole, tert-butyl N-[4-(4,4,5,5-tetramethyl-1,2,3-dioxaborolan-2-yl)phenyl]carbamate, phenylboronic acid, 3-acetylphenylboronic acid, boron trifluoride-acetic acid complex, boron trifluoride-sulfolane complex, 2-thiopheneboronic acid and tris(trimethylsilyl)borate.

[0038]

Examples of phosphorus compounds include inorganic phosphorus compounds and organic phosphorus compounds. Examples of inorganic phosphorus compounds include ammonium polyphosphate.

[0039]

Examples of the organophosphorus compound include phosphates such as trimethyl phosphate, triethyl phosphate, tripropyl phosphate, tributyl phosphate, tripentyl phosphate, trihexyl phosphate, dimethyl ethyl phosphate, methyl dibutyl phosphate, ethyl dipropyl phosphate, 2-ethylhexyl di(p-tolyl) phosphate, bis(2-ethylhexyl)p-tolyl phosphate, tritolyl phosphate, di(dodecyl)p-tolyl phosphate, tris(2-butoxyethyl) phosphate, tricyclohexyl phosphate, triphenyl phosphate, ethyl diphenyl phosphate, dibutyl phenyl phosphate, phenylbisdodecyl phosphate, cresyl diphenyl phosphate, tricresyl phosphate, p-tolyl bis(2,5,5'-trimethylhexyl) phosphate, cresyl-2,6-xylenyl phosphate, trixylenyl phosphate, hydroxyphenyl diphenyl phosphate, tris(tert-butylphenyl) phosphate, tris(isopropylphenyl) phosphate, 2-ethylhexyldiphenylphosphate, bis(2-ethylhexyl)phenylphosphate, tri(nonylphenyl)phosphate and phenylbisneopentylphosphate;

condensed phosphates such as 1,3-phenylene bis(diphenylphosphate), 1,4-phenylene bis(dixylenylphosphate), 1,3-phenylene bis(3,5,5'-trimethylhexylphosphate), bisphenol A bis(diphenylphosphate), 4 ,4'-biphenyl bis(dixylenylphosphate) and 1,3,5-phenylene tris(dixylenylphosphate),

phosphites such as trimethyl phosphite, triethyl phosphite, triphenyl phosphite and tricresyl phosphite; and

phosphites such as 1,3-phenylene bis(diphenylphosphite), 1,3-phenylene bis(dixylenylphosphite), 1,4-phenylene bis(3,5,5'-trimethylhexylphosphite), bisphenol A bis(diphenylphosphite), 4, 4'-biphenyl bis(dixylenylphosphite) and 1,3,5-phenylene tris(dixylenylphosphite).

[0040]

Examples of the nickel compound include divalent nickel halides such as nickel(II) chloride, nickel(II) bromide and nickel(II) iodide, inorganic nickel compounds such as nickel(II) acetate and nickel(II) carbonate, and organic nickel compounds such as nickel bis(ethyl acetoacetate) and nickel bis(acetylacetonate).

[0041]

Examples of the titanium compound include inorganic titanium compounds such as titanium dioxide, titanium nitride, strontium titanate, lead titanate, barium titanate and potassium titanate; tetraalkoxytitanium such as tetraethoxytitanium, tetraisopropoxytitanium and tetrabutyloxytitanium; and organic titanium compounds such as tetraethylene glycol titanate, di-n-butyl bis(triethanolamine)titanate, diisopropoxytitanium bis(acetylacetonate), isopropoxytitanium octanoate, isopropyl titanium trimethacrylate, isopropyl titanium triacrylate, isopropyl triisostearoyl titanate, isopropyl tridecylbenzenesulfonyl titanate, isopropyl tris(butyl methyl pyrophosphate)titanate, tetraisopropyl di(dilauryl phosphite)titanate, dimethacryloxyacetate titanate, diacryloxyacetate titanate, di(dioctyl phosphate)ethylene titanate, isopropoxy titanium tri(dioctyl phosphate), isopropyl tris(dioctyl pyrophosphate)titanate, tetraisopropyl bis(dioctyl phosphite) titanate, tetraoctyl bis(ditridecyl phosphite)titanate, tetra(2,2-diallyloxymethyl-1-butyl) bis(ditridecyl)phosphite titanate, bis(dioctylpyrophosphate)oxyacetate titanate, tris(dioctylpyrophosphate)ethylene titanate, isopropyltri-n-dodecylbenzenesulfonyl titanate, isopropyltrioctanoyl titanate, isopropyl dimethacryloyl isostearoyl titanate, isopropyl isostearoyl titanate acrylic titanate, isopropyl tri(dioctyl phosphate) titanate, isopropyl tricumylphenyl titanate and isopropyl tri(N-aminoethylaminoethyl) titanate.

[0042]

Examples of the cobalt compound include inorganic cobalt compounds such as cobalt salts of inorganic acids, cobalt halides, cobalt oxide, cobalt hydroxide, dicobalt octacarbonyl, cobalt hydrotetracarbonyl, tetracobalt dodecacarbonyl, and alkylidenetricobalt nonacarbonyl; cobalt salts of organic acids (e.g. acetate, propionate, cyanide, naphthenate and stearate; alkyl sulfonates (e.g. C _6-18 alkyl sulfonates) such as methanesulfonate, ethanesulfonate, octanesulfonate and dodecanesulfonate; arylsulfonates which may be substituted with an alkyl group (e.g. C _6-18 alkyl arylsulfonates) such as benzenesulfonate, p-toluenesulfonate, naphthalenesulfonate, decylbenzenesulfonate and dodecylbenzenesulfonate) such as cobalt tris(acetyl acetate) and cobalt tris(acetylacetonate); and organic cobalt complexes. Examples of the ligand constituting the complex include hydroxy (OH), alkoxy (e.g. methoxy, ethoxy, propoxy and butoxy), acyl (e.g. acetyl and propionyl), alkoxy, carbonyl (e.g. methoxycarbonyl and ethoxycarbonyl), acetylacetonate, cyclopentadienyl group, halogen atoms (e.g. chlorine and bromine), CO, CN, oxygen atom, aquo ( _H2O ), phosphorus compounds such as phosphine (e.g. triarylphosphines such as triphenylphosphine), and nitrogen-containing compounds such as ammine ( _NH3 ), NO, nitro ( _NO2 ), nitrato ( _NO3 ), ethylenediamine, diethylenetriamine, pyridine and phenanthroline.

[0043]

Examples of xenon compound include fluorides such as _XeF2 , _XeF4 , _XeF6 , _XeOF2 , _XeOF4 and _XeO2F4 , oxides such as _XeO3 and _XeO4 , xenonic acid Xe(OH) ₆ and its _{salt Ba3XeO6 ,} perxenonic acid _H4XeO6 and its _{salt Na4XeO6} , metal carbonyl complexes M(CO) _5Xe (M=Cr _, Mo _, W) and hydrates.

[0044]

Examples of the chromium compound include chromium acetylacetone complexes such as chromium acetylacetone; chromium alkoxide such as chromium(III) isopropoxide; organic acid chromium such as chromium(II) acetate and chromium(III) acetate hydroxide; organic chromium compounds such as tris(allyl)chromium, tris(methallyl)chromium, tris(crotyl)chromium, bis(cyclopentadienyl)chromium (i.e. chromocene), bis(pentamethylcyclopentadienyl)chromium (i.e. decamethylchromocene), bis(benzene)chromium, bis(ethylbenzene)chromium, bis(mesitylene)chromium, bis(pentadienyl)chromium, bis(2,4-dimethylpentadienyl)chromium, bis(allyl)tricarbonylchromium, (cyclopentadienyl)(pentadienyl)chromium, tetra(1-norbornyl)chromium, (trimethylenemethane)tetracarbonylchromium, bis(butadiene)dicarbonylchromium, (butadiene)tetracarbonylchromium and bis(cyclooctatetraene)chromium.

[0045]

Examples of the tungsten compound include inorganic tungsten compounds such as tungsten trioxide, ammonium tungstate and sodium tungstate; and organic tungsten compounds such as tungsten complexes coordinated by boron atoms, such as those coordinated by ethylborylethylidene ligands; tungsten complexes coordinated by carbon atoms, such as those coordinated by carbonyl ligands, cyclopentadienyl ligands, alkyl group ligands and olefin-based ligands; tungsten complexes coordinated by nitrogen atoms, such as those coordinated by pyridine ligands and acetonitrile ligands; tungsten complexes coordinated by phosphorus atoms, such as those coordinated by phosphine ligands and phosphite ligands; and tungsten complexes coordinated by sulfur atoms, such as those coordinated by diethylcarbamodithioate ligands.

[0046]

Examples of the thallium compound include inorganic thallium compounds such as thallium nitrate, thallium sulfate, thallium fluoride, thallium chloride, thallium bromide, and thallium iodide; organic thallium compounds such as trialkylthallium such as trimethylthallium, triethylthallium, and triisobutylthallium; arylthallium such as dialkylthallium halide, alkenyldialkylthallium, alkynyldialkylthallium, triphenylthallium, and tritolylthallium; diaryltallium halide, thallium 2-ethylhexanoate, thallium malonate, thallium formate, thallium ethoxide, and thallium acetylacetonate.

[0047]

Examples of the zirconium compound include inorganic zirconium compounds such as zirconium nitrate, zirconium sulfate, zirconium carbonate, zirconium hydroxide, zirconium fluoride, zirconium chloride, zirconium bromide and zirconium iodide; and organic zirconium compounds such as zirconium n-propoxide, zirconium n-butoxide, zirconium tert-butoxide, zirconium isopropoxide, zirconium ethoxide, zirconium acetate, zirconium acetylacetonate, zirconium butoxyacetylacetonate, zirconium bisacetylacetonate, zirconium ethyl acetoacetate, zirconium acetylacetonate bisethyl acetoacetate, zirconium hexafluoroacetylacetonate and zirconium trifluoroacetylacetonate.

[0048]

Examples of the zinc compound include diethylzinc, dimethylzinc, zinc acetate, zinc nitrate, zinc stearate, zinc oleate, zinc palmitate, zinc myristate, zinc dodecanoate, zinc acetylacetonate, zinc chloride, zinc bromide, zinc iodide, and zinc carbamate.

[0049]

Examples of the silver compound include organic silver compounds such as silver acetate, silver pivalate, silver trifluoromethanesulfonate, and silver benzoate; and inorganic silver compounds such as silver nitrate, silver fluoride, silver chloride, silver bromide, silver iodide, silver sulfate, silver oxide, silver sulfide, silver tetrafluoroborate, silver hexafluorophosphate (AgPF ₆ ), and silver hexafluoroantimonate (AgSbF ₆ ).

[0050]

Examples of the aluminum compound include inorganic aluminum compounds such as aluminum oxide; alkoxy compounds such as trimethoxyaluminum, triethoxyaluminum, isopropoxyaluminum, isopropoxydiethoxyaluminum and tributoxyaluminum; acyloxy compounds such as triacetoxyaluminum, aluminum tristearate and aluminum tributyrate; and organic aluminum compounds such as aluminum isopropylate, aluminum sec-butoxide, aluminum tert-butoxide, aluminum tris(ethyl acetoacetate), aluminum tris(hexafluoroacetylacetonate), aluminum tris(ethyl acetoacetate), aluminum tris(n-propyl acetoacetate), aluminum tris(isopropyl acetoacetate), aluminum tris(n-butyl acetoacetate), aluminum tris(salicyaldehyde), aluminum tris(2-ethoxycarbonylphenolate), aluminum tris(acetylacetonate), trialkylaluminum compounds such as trimethylaluminum, triethylaluminum and triisobutylaluminum, dialkylaluminum halide, alkenyldialkylaluminum, alkynyldialkylaluminum, arylaluminum such as triphenylaluminum and tritolylaluminum, and diarylaluminum halides.

[0051]

Examples of the vanadium compound include vanadic acid and metavanadic acid and inorganic vanadium compounds or alkali metal salts thereof; alkoxides such as triethoxyvanadyl, pentaethoxyvanadium, triamyloxyvanadyl and triisopropoxyvanadyl; acetonates such as vanadyl bisacetylacetonate, vanadium acetylacetonate, vanadyl acetylacetonate and vanadium oxyacetylacetonate; and organic vanadium compounds such as vanadium stearate, vanadium pivalate and vanadium acetate.

[0052]

Examples of the niobium compound include halides such as niobium(V) chloride and niobium(V) fluoride; inorganic niobium compounds such as niobium sulfate, niobic acid, and niobate; and organic niobium compounds such as niobium alkoxide.

[0053]

Examples of the tantalum compound include inorganic tantalum compounds such as TaCl ₅ and TaF ₅ ; and organic tantalum compounds such as Ta(OC ₂ H ₅ ) ₅ , Ta(OCH ₃ ) ₅ , Ta(OC ₃ H ₇ ) ₅ , Ta(OC ₄ H ₉ ) ₅ , (C ₅ H ₅ ) ₂ TaH ₃ , and Ta(N(CH ₃ ) ₂ ) ₅ .

[0054]

Examples of the molybdenum compound include inorganic molybdenum compounds such as molybdenum trioxide, zinc molybdate, ammonium molybdate, magnesium molybdate, calcium molybdate, barium molybdate, sodium molybdate, potassium molybdate, phosphomolybdic acid, ammonium phosphomolybdate, sodium phosphomolybdate, silicolybdic acid, molybdenum disulfide, molybdenum diselenide, molybdenum ditelluride, molybdenum boride, molybdenum disilicide, molybdenum nitride, and molybdenum carbide; and organic molybdenum compounds such as molybdenum dialkyl dithiophosphate and molybdenum dialkyl dithiocarbamate.

[0055]

Examples of the manganese compound include inorganic manganese compounds such as manganese hydroxides, nitrates, acetates, sulfates, chlorides, and carbonates; and organic manganese compounds including manganese oxalate, acetylacetonate compounds, and manganese alkoxide such as methoxide, ethoxide, or butoxide.

[0056]

Examples of the iron compound include inorganic iron compounds such as iron(II) fluoride, iron(III) fluoride, iron(II) chloride, iron(III) chloride, iron(II) bromide, iron(III) bromide, iron(II) iodide, iron(III) iodide, iron(II) oxide, iron(III) oxide, triiron(II, III) tetroxide, iron(II) sulfate, iron(III) sulfate, iron(II) nitrate, iron(III) nitrate, iron(II) hydroxide, iron(III) hydroxide, iron(II) perchlorate, iron(III) perchlorate, iron(II) ammonium sulfate, iron(III) ammonium sulfate, iron(III) tungstate oxide, iron(III) tetravanadate, iron(II) selenide, iron(II) titanium trioxide, diiron(III) titanium pentoxide, iron(II) sulfide, iron(III) sulfide, diiron(II) phosphide, triiron(II) and iron(III) phosphide; and organic iron compounds such as iron(II) acetate, iron(III) acetate, iron(II) formate, iron(III) triformate, iron(II) tartrate, sodium iron(III) tartrate, iron(II) lactate, iron(II) oxalate, iron(III) oxalate, iron(III) ammonium citrate, iron(III) laurate, iron(III) stearate, iron(III) tripalmitate, potassium hexacyanoferrate(II), potassium hexacyanoferrate(III), bis(2,4-pentanedionato)diaqua iron(II), tris(2,4-pentanedionato)iron(III), potassium tris(oxalato)ferrate(III), iron(III) tris(trifluoromethanesulfonate), iron(III) p-toluenesulfonate, iron(III) dimethyldithiocarbamate, iron(III) diethyldithiocarbamate and ferrocene.

[0057]

Examples of the copper compound include organic copper compounds such as copper oxalate, copper stearate, copper formate, copper tartrate, copper oleate, copper acetate, copper gluconate, and copper salicylate; and inorganic copper compounds such as copper carbonate, copper chloride, copper bromide, copper iodide, copper phosphate, and natural minerals such as hydrotalcite, stichtite, and pyrolite.

[0058]

Examples of the cadmium compound include inorganic cadmium compounds such as cadmium fluoride, cadmium chloride, cadmium bromide, cadmium iodide, cadmium oxide, and cadmium carbonate; and organic cadmium compounds such as cadmium phthalate and cadmium naphthalate.

[0059]

Examples of mercury compounds include inorganic mercury compounds such as mercury(II) chloride, mercury sulfate, and mercury(II) nitrate; and organic mercury compounds such as methylmercury, methylmercury chloride, ethylmercury, ethylmercury chloride, phenylmercuric acetate, thimerosal, para-chloromercuribenzoate, and fluorescein mercury acetate.

[0060]

Examples of the gallium compound include organic gallium compounds such as tetraphenylgallium and tetrakis(3,4,5-trifluorophenyl)gallium; and inorganic gallium compounds such as gallium oxoate, gallium halides, gallium hydroxide, and gallium cyanide.

[0061]

Examples of the indium compound include organic indium compounds such as indium triethoxyindium, indium 2-ethylhexanoate, and indium acetylacetonate; and inorganic indium compounds such as indium cyanide, indium nitrate, indium sulfate, indium carbonate, indium fluoride, indium chloride, indium bromide, and indium iodide.

[0062]

Examples of the arsenic compound include inorganic arsenic compounds such as diarsenic trioxide, diarsenic pentoxide, arsenic trichloride, arsenic pentoxide, as well as arsenous acid and arsenic acid and their salts including sodium arsenite, ammonium arsenite, potassium arsenite, ammonium arsenate and potassium arsenate; and organic arsenic compounds such as dimethylarsinic acid, phenylarsonic acid, diphenylarsonic acid, p-hydroxyphenylarsonic acid, p-aminophenylarsonic acid and their salts including sodium cacodylate and potassium cacodylate.

[0063]

Examples of the antimony compound include inorganic antimony compounds such as antimony oxide, antimony phosphate, KSb(OH) and _NH4SbF6 ; and organic antimony compounds such as antimony esters of organic acids, cyclic alkyl antimony and _{triphenylantimony} .

[0064]

Examples of the bismuth compound include organic bismuth compounds such as triphenylbismuth, bismuth 2-ethylhexanoate, and bismuth acetylacetonate; and inorganic bismuth compounds such as bismuth nitrate, bismuth sulfate, bismuth acetate, bismuth hydroxide, bismuth fluoride, bismuth chloride, bismuth bromide, and bismuth iodide.

[0065]

Examples of selenium compounds include organic selenium compounds such as selenomethionine, selenocysteine, and selenocystine; and inorganic selenium compounds such as alkali metal selenates such as potassium selenate, and alkali metal selenites such as sodium selenite.

[0066]

Examples of tellurium compound include telluric acid and its salts, tellurium oxide, tellurium chloride, tellurium bromide, tellurium iodide, and tellurium alkoxide.

[0067]

Examples of the magnesium compound include organic magnesium compounds such as magnesium ethyl acetoacetate monoisopropylate, magnesium bis(ethyl acetoacetate), magnesium allyl acetoacetate monoisopropylate, and magnesium bis(acetylacetonate); and inorganic magnesium compounds such as magnesium oxide, magnesium sulfate, magnesium nitrate, and magnesium chloride.

[0068]

Examples of the calcium compound include organic calcium compounds such as calcium 2-ethylhexanoate, calcium ethoxide, calcium methoxide, calcium methoxyethoxide, and calcium acetylacetonate; and inorganic calcium compounds such as calcium nitrate, calcium sulfate, calcium carbonate, calcium phosphate, calcium hydroxide, calcium cyanide, calcium fluoride, calcium chloride, calcium bromide, and calcium iodide.

[0069]

As a compound in which the element to be used for doping nanodiamonds is Li, Na, K, Cs, S, Sr, Ba, F, Y or lanthanides, a known organic or inorganic compound can be used.

[0070]

The amount of explosive in the composition comprising the explosive and the compound of the element of group 14 and, if necessary, the compound of the third element is preferably from 80 to 99.9999% by weight, more preferably from 85 to 99.999% by weight, even more preferably from 90 to 99.99% by weight and particularly preferably from 95 to 99.9% by weight. The amount of the compound of the element of group 14 is preferably from 0.0001 to 20% by weight, more preferably from 0.001 to 15% by weight, even more preferably from 0.01 to 10% by weight and particularly preferably from 0.1 to 5% by weight. The amount of the compound of the third element is preferably from 0 to 20% by mass, more preferably from 0.001 to 15% by mass, even more preferably from 0.01 to 10% by mass, and particularly preferably from 0.02 to 8% by mass. Furthermore, the content of the element of group 14 in the mixture comprising the explosive and the compound of the element of group 14 and, if necessary, the third element is preferably from 0.000005 to 10% by weight, more preferably from 0.00001 to 8% by weight, even more preferably from 0.0001 to 5% by weight, particularly preferably from 0.001 to 3% by weight and most preferably from 0.01 to 1% by weight, and the content of the third element is preferably from 0 to 10% by weight, more preferably from 0.00001 to 8% by weight, even more preferably from 0.00002 to 5% by weight, particularly preferably from 0.00003 to 3% by weight and most preferably from 0.00004 to 2% by weight.

[0071]

Preferred doped nanodiamonds obtained by the manufacturing method according to an embodiment of the present invention contain preferably from 0.001 to 100 mol, more preferably from 0.002 to 10 mol, and even more preferably from 0.003 to 5 mol of the third element relative to 1 mol of the element of group 14.

[0072]

Mixing of the explosive and the compound of the element of group 14 and, if necessary, the compound of the third element may be carried out by mixing the powders in case they are solids, by melting or by mixing by dissolving or dispersing them in a suitable solvent. Mixing may also be carried out by stirring, grinding in a ball mill or by means of ultrasonic waves.

[0073]

In one preferred embodiment, the explosive composition comprising an explosive substance and a compound of a group 14 element and, optionally, a compound of a third element, further comprises a cooling medium. The cooling medium may be solid, liquid or gaseous. Examples of a method of using a cooling medium include a method of detonating a mixture of an explosive substance and a compound of a group 14 element and, optionally, a compound of a third element, in a cooling medium. Examples of a cooling medium include inert gases (nitrogen, argon, CO), water, ice, liquid nitrogen, aqueous solutions of salts containing group 14 elements, crystalline hydrates, aqueous solutions of salts containing a third element and crystalline hydrates. Examples of a salt containing a group 14 element include ammonium hexafluorosilicate, ammonium silicate and tetramethylammonium silicate. The cooling medium is preferably used in an amount exceeding about 5 times the mass of the explosive substance, for example in the case of water or ice.

[0074]

In one preferred embodiment of the present invention, an explosive composition containing an explosive substance and a compound of a group 14 element and, if necessary, a compound of a third element is converted into diamonds by compression by a shock wave under conditions of high pressure and high temperatures created by the explosion of the explosive substance (detonation method). During the explosion of the explosive substance, at least one element of group 14 and, if necessary, at least one third element are embedded in a diamond lattice. The carbon source of the nanodiamonds can be an explosive substance and an organic compound of a group 14 element and, if necessary, a compound of a third element; however, in the case where the mixture containing an explosive substance and a compound of a group 14 element and, if necessary, a compound of a third element, additionally contains a carbon material that does not contain either an element of group 14 or a third element, this carbon material can be a carbon source of the nanodiamonds.

[0075]

In the manufacturing method and the cleaning method according to the embodiments of the present invention, cleaning the nanodiamond composition doped with a group 14 element and, if necessary, a third element that contains a group 14 element and/or its oxide and, if necessary, a third element of the group of elements and/or its oxide, includes alkaline treatment and can be performed by a combination of alkaline treatment and mixed acid treatment. The preferred cleaning is a combination of alkaline treatment and mixed acid treatment (the order is not specified).

[0076]

Examples of the mixed acid include a mixed acid composed of concentrated sulfuric acid and concentrated nitric acid, wherein the mixed acid is preferably a mixed acid composed of concentrated sulfuric acid and concentrated nitric acid in a ratio of 1:1 (volume ratio). The temperature of the mixed acid treatment is from 50 to 200°C, and the duration of the mixed acid treatment is from 0.5 to 24 hours.

[0077]

Examples of alkali include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide. Examples of alkali metal hydroxide include 0.1-10N aqueous alkali metal hydroxide solution. The alkali treatment temperature is 30 to 150°C, and the alkali treatment time is 0.5 to 24 hours.

[0078]

In the case where an explosive composition containing an explosive substance and a compound of an element of group 14 and, if necessary, a third element, explodes in a container, in addition to doped nanodiamonds, for example, graphite, metal impurities, an element of group 14 elements (elementary Si, elemental Ge, elemental Sn, elemental Pb), oxides of elements of group 14 (SiO ₂ , GeO ₂ , SnO ₂ , PbO ₂ ), a third element of group elements and oxides of a third element are formed. Graphite, metal impurities, a third element of group elements and oxides of a third element can be removed by mixed acid treatment, and an element of group 14 elements and oxides of elements of group 14 can be removed by alkaline treatment.

[0079]

Nanodiamonds doped with an element of group 14 and, optionally, a third element of a preferred embodiment, obtained by a manufacturing method or a purification method according to an embodiment of the present invention, have a fluorescence emission peak in the range from 720 to 770 nm and satisfy requirement (i) and/or (ii):

(i) the specific surface area determined by the BET method is from 20 to 900 ^m2 /g, and

(ii) the average size of primary particles ranges from 2 to 70 nm.

[0080]

The doped nanodiamonds obtained by the manufacturing method or the purification method according to the preferred embodiment of the present invention have a vacancy center of a Group 14 element (V) and, if necessary, further have a vacancy center of a third element, and thus have a fluorescence emission peak. In the case where the Group 14 element is Si, the wavelength of the fluorescence emission peak is preferably from 720 to 770 nm, and more preferably from 730 to 760 nm, in the case where the Group 14 element contains silicon; is preferably from 580 to 630 nm, and more preferably from 590 to 620 nm, in the case where the Group 14 element contains germanium; is preferably from 590 to 650 nm, and more preferably from 600 to 640 nm, in the case where the Group 14 element contains tin; and is preferably from 540 to 600 nm, and more preferably from 550 to 590 nm, in the case where the group 14 element contains lead. In one preferred embodiment of the present invention, the fluorescence emission peak of the nanodiamonds in which the group 14 element is Si has a sharp peak at a wavelength of about 738 nm, which is called a zero-phonon level (ZPL).

[0081]

The concentration of a vacancy center of a Group 14 element of the nanodiamonds doped with a Group 14 element and, if necessary, a third element obtained by the manufacturing method or purification method according to an embodiment of the present invention is preferably 1× ¹⁰¹⁰ / ^cm3 or more, and more preferably from 2× ¹⁰¹⁰ to 1× ¹⁰¹⁹ / ^cm3 , wherein the concentration of a vacancy center of the third element is preferably 1× ¹⁰¹⁰ / ^cm3 or more, and more preferably from 2× ¹⁰¹⁰ to 1× ¹⁰¹⁹ / ^cm3 or more. It is contemplated that the concentrations of a vacancy center of a Group 14 element and a vacancy center of the third element can be determined using, for example, a confocal laser microscope or a fluorescence and absorption spectrometer. It should be noted that, to determine the concentration of MV center (M is a group 14 element or the third element) by fluorescence and absorption spectrometry, the literature (DOI 10.1002/pssa.201532174) can be used as reference material.

[0082]

The specific surface area measured by the BET method of the nanodiamonds doped with a Group 14 element and, if necessary, a third element obtained by the manufacturing method or the purification method according to the embodiment of the present invention is preferably 20 to 900 ^m2 /g, more preferably 25 to 800 ^m2 /g, still more preferably 30 to 700 ^m2 /g, and particularly preferably 35 to 600 ^m2 /g. The specific surface area measured by the BET method can be determined by nitrogen adsorption. Examples of an apparatus for measuring the specific surface area by the BET method include BELSORP-mini II (available from Microtrac BEL), and, for example, the specific surface area determined by the BET method can be measured under the following conditions.

• Measured amount of powder: 40 mg.

• Pre-drying: treatment at 120°C for 3 hours under vacuum.

• Measurement temperature: -196°C (liquid nitrogen temperature)

The average size of the primary particles of the doped nanodiamonds obtained by the manufacturing method or the purification method according to the embodiment of the present invention is preferably 2 to 70 nm, more preferably 2.5 to 60 nm, even more preferably 3 to 55 nm, and particularly preferably 3.5 to 50 nm. The average size of the primary particles can be determined by the Scherrer equation based on the results of powder X-ray diffractometry (XRD) analysis. Examples of the XRD measuring device include a multi-purpose X-ray diffraction system with built-in intelligent control (available from Rigaku Corporation).

[0083]

The carbon content of the doped nanodiamonds obtained by the manufacturing method or the purification method according to an embodiment of the present invention is preferably from 70 to 99% by weight, more preferably from 75 to 98% by weight, and even more preferably from 80 to 97% by weight.

[0084]

The hydrogen content in the doped nanodiamonds obtained by the manufacturing method or the purification method according to an embodiment of the present invention is preferably from 0.1 to 5% by weight, more preferably from 0.2 to 4.5% by weight, and even more preferably from 0.3 to 4.0% by weight.

[0085]

The nitrogen content of the doped nanodiamonds obtained by the manufacturing method or the purification method according to an embodiment of the present invention is preferably from 0.1 to 5% by weight, more preferably from 0.2 to 4.5% by weight, and even more preferably from 0.3 to 4.0% by weight.

[0086]

The content of carbon, hydrogen and nitrogen in the doped nanodiamond obtained by the manufacturing method or the purification method according to an embodiment of the present invention can be measured by elemental analysis.

[0087]

The content of the Group 14 element of the doped nanodiamonds obtained by the manufacturing method or the purification method according to the embodiment of the present invention is preferably from 0.0001 to 10.0% by mass, more preferably from 0.0001 to 5.0% by mass, and even more preferably from 0.0001 to 1.0% by mass, and the content of the third element is preferably from 0.0001 to 10.0% by mass, more preferably from 0.0001 to 5.0% by mass, and even more preferably from 0.0001 to 1.0% by mass. The content of group 14 elements and the content of the third element can be determined, for example, by inductively coupled plasma emission spectrometry (ICP-AES, XRF, secondary ion mass spectrometry (SIMS)), and after alkaline melting, the doped nanodiamonds can be quantified as an acidic solution.

[0088]

For the doped nanodiamonds obtained by the manufacturing method or the purification method according to the preferred embodiment of the present invention, the characteristic peaks of diamond, graphite, surface hydroxyl groups (OH) and surface carbonyl groups (CO) can be identified in the Raman shift diagram by means of Raman spectroscopy. The characteristic peak of diamond in the Raman shift diagram is in the range of 1100 to 1400 cm ^-1 , the characteristic peak of graphite is in the range of 1450 to 1700 cm ^-1 , the characteristic peak of the surface hydroxyl group (OH) is in the range of 1500 to 1750 cm ^-1 , and the characteristic peak of the surface carbonyl group (CO) is in the range of 1650 to 1800 cm ^-1 . The characteristic peak regions of diamond, graphite, surface hydroxyl group (OH) and surface carbonyl group (CO) can be determined by a Raman spectrometer. The wavelength of the laser of the Raman scattering source is, for example, 325 nm or 488 nm. A Raman confocal microscope spectrometer (e.g., trade name: Confocal Raman Microscope LabRAM HR Evolution, available from Horiba, Ltd.) can be used as the Raman spectrometer.

[0089]

In the doped nanodiamonds of a preferred embodiment obtained by the manufacturing method or the purification method according to the embodiment of the present invention, the ratio (D/G) of the peak area (D) of diamond to the peak area (G) of graphite is preferably from 0.2 to 9, more preferably from 0.3 to 8, and even more preferably from 0.5 to 7.

[0090]

In the doped nanodiamonds of a preferred embodiment obtained by the manufacturing method or the purification method according to the embodiment of the present invention, the ratio (H/D) of the peak area (H) of the surface hydroxyl group (OH) and the peak area (D) of the diamond is preferably from 0.1 to 5, more preferably from 0.1 to 4.0, and even more preferably from 0.1 to 3.0.

[0091]

In the doped nanodiamonds of a preferred embodiment obtained by the manufacturing method or the purification method according to an embodiment of the present invention, the ratio (C/D) of the peak area (C) of the surface carbonyl group (CO) and the peak area (D) of the diamond is preferably from 0.01 to 1.5, more preferably from 0.03 to 1.2, and even more preferably from 0.05 to 1.0.

[0092]

With regard to the Raman spectroscopy method for nanodiamonds, the literature can be used as reference (e.g. Vadym N. Mochalin et al., NATURE NANOTECHNOLOGY, 7 (2012) 11–23, in particular figure 3).

[0093]

In another preferred embodiment of the present invention, the surface of the doped nanodiamonds obtained by the manufacturing method or the purification method according to an embodiment of the present invention may have at least one oxygen-containing end functional group and/or at least one hydrogen-containing end group. Examples of the oxygen-containing end functional group include OH, COOH, CONH ₂ , C=O and CHO, with OH, C=O and COOH being preferred. Examples of the hydrogen-containing end group include alkyl groups containing from 1 to 20 carbon atoms.

[0094]

The presence of at least one oxygen-containing end functional group on the surface of doped nanodiamonds is preferable because the aggregation of nanodiamond particles can be suppressed. The presence of at least one hydrogen-containing end group on the surface of doped nanodiamonds is preferable because the zeta potential becomes positive and stable and high dispersion is observed in an acidic aqueous solution.

[0095]

In another preferred embodiment of the present invention, the doped nanodiamonds obtained by the manufacturing method or the purification method according to an embodiment of the present invention may have a core-shell structure. The core of the doped nanodiamonds having a core-shell structure is a particle of nanodiamond doped with an element of group 14 and, if necessary, a third element. This core is preferably a core having a vacancy center of an element of group 14 and, if necessary, additionally having a vacancy center of a third element and emitting fluorescence. The shell is a non-diamond coating layer, may contain sp2 carbon and preferably additionally contains an oxygen atom. The shell may be a graphite layer. The thickness of the shell is preferably 5 nm or less, more preferably 3 nm or less, and even more preferably 1 nm or less. The shell may have a hydrophilic functional group on its surface.

[0096]

Preferably, the doped nanodiamonds can be produced by detonation. The shape of the doped nanodiamonds is preferably spherical, ellipsoidal or close to them polyhedral.

[0097]

In the present description, the degree of roundness corresponds to a numerical value representing the complexity of the shape illustrated, for example, in the image. For the degree of roundness, the numerical value becomes smaller as the shape becomes more complex, while its maximum value is 1. The degree of roundness can be determined, for example, by analyzing a TEM image of a doped nanodiamond using image analysis software (e.g., winROOF) and using the following equation.

Degree of roundness = 4π × (area) ÷ (circumference)^2

For example, in the case of a perfect circle having a radius of 10, the calculation equation becomes “4π × (10 × 10 × π) ÷ (10 × 2 × π)^2”, and the roundness degree results in 1 (the maximum value). That is, in terms of the roundness degree, the perfect circle is the least complex shape. The roundness degree of the doped nanodiamond is preferably 0.2 or more, more preferably 0.3 or more, and still more preferably 0.35 or more.

[0098]

In one preferred embodiment of the present invention, the center of the doped nanodiamond particle has a diamond structure comprising carbon atoms in the sp3 hybridization state and a doped element of group 14 and, if necessary, a third element, and its surface is covered with an amorphous layer formed from carbon atoms in the sp2 state. In a more preferred embodiment, the outer side of the amorphous layer can be covered with a graphite oxide layer. In addition, a hydration layer can be formed between the amorphous layer and the graphite oxide layer.

[0099]

In one preferred embodiment of the present invention, the doped nanodiamonds obtained by the manufacturing method or the purification method according to an embodiment of the present invention have a positive or negative zeta potential. The zeta potential of the doped nanodiamond is preferably from -70 to 70 mV, and more preferably from -60 to 30 mV.

[0100]

Doped nanodiamonds can be manufactured by a production method comprising mixing an explosive composition containing an explosive substance and a compound of group 14 and, if necessary, a compound of a third element, and detonating the resulting mixture in a sealed container. Examples of the container include metal containers and containers made of synthetic resin. The explosive composition containing an explosive substance and a compound of group 14 and, if necessary, a compound of a third element is preferably formed by pressing or casting. Examples of a method for producing particles (dry powder) of each of the explosive substance, the compound of group 14 and the compound of the third element include crystallization, crushing and rapid spray evaporation. In the case where the explosive composition is formed by pressing or casting, the explosive substance and the compound of group 14 and, if necessary, the compound of the third element are mixed in the form of a dry powder, in a molten state or using a solvent. The state at the time of mixing of the explosive and the compound of the element of Group 14 may be any of the following four combinations:

Explosive (dry powder) and compound of element group 14 (dry powder)

Explosive (dry powder) and compound of element group 14 (molten state)

Explosive (molten state) and compound of element group 14 (dry powder)

Explosive (molten state) and compound of element group 14 (molten state)

In the case where the explosive composition is formed by further mixing the compound of the third element, the compound of the third element may be in the form of a dry powder or in a molten state, and there are eight possible combinations of dry powder and molten state for mixing the explosive, the compound of the element of group 14 and the compound of the third element.

[0101]

The mixing of the explosive and the compound of the element of group 14 and, if necessary, the compound of the third element may be carried out in the presence or absence of a solvent, and the shaping may be carried out by pressing or casting after mixing.

[0102]

The average particle diameters of the explosive, the compound of the element of group 14 and the compound of the third element are preferably 10 mm or less, more preferably 5 mm or less and even more preferably 1 mm or less. It should be noted that these average particle diameters can be measured by laser diffraction/scattering methods, by means of an optical microscope or by a Raman scattering method.

[0103]

The product obtained by explosion is further subjected to alkali treatment and, if necessary, can be further purified, including mixed acid treatment and subsequent processing.

[0104]

The subsequent processing may include annealing and gas-phase oxidation. The group 14 element and, if necessary, the third element included in the doped nanodiamond are brought into contact with the vacancy by means of the annealing treatment, and thus a vacancy center of the group 14 element and, if necessary, a vacancy center of the third element can be formed. In addition, by means of the gas-phase oxidation, the graphite layer formed on the surface of the doped nanodiamond can be reduced or removed. The formation of vacancies can be performed before the annealing, although such formation of vacancies is an optional process. The formation of a vacancy is carried out by irradiation with an ion or electron beam. Even in the case where the formation of a vacancy does not occur, the vacancy center of the group 14 element and, if necessary, the vacancy center of the third element are formed by annealing; However, upon annealing, after the vacancy is formed, more vacancy centers of the Group 14 element and, if necessary, vacancy centers of the third element can be formed. For the vacancy density introduced by irradiation with an ion beam or an electron beam, the upper limit is limited by the concentration at which the diamond is damaged (vacancy concentration>1 × 10 ²¹ /cm ³ ), but the lower limit is, for example, 1 × 10 ¹⁶ /cm ³ or higher, or even 1 × 10 ¹⁸ /cm ³ or higher. The ion beam is preferably a hydrogen (H) or helium (He) ion beam. For example, the energy of the hydrogen ion beam is preferably 10 to 1500 keV, and the energy of the helium ion beam is preferably 20 to 2000 keV. The energy of the electron beam is preferably 500 to 5000 keV.

[0105]

The annealing temperature is preferably 800°C or higher, and the annealing time is 30 minutes or more.

[0106]

The gas phase oxidation can be carried out in an air atmosphere, the gas phase oxidation temperature is preferably 300°C or higher, and the gas phase oxidation time is 2 hours or more.

EXAMPLES

[0107]

Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

Examples 1-6

Using TNT as an explosive and using the dopant specified in Table 1 as a compound of a Group 14 element in the amount of moles specified in Table 1 relative to 1 mole of TNT, the production of silicon-doped nanodiamonds was carried out by detonation according to a conventional method under conditions including the temperature (K) and pressure (GPa) shown in Table 1, and thus silicon-doped nanodiamonds in the proportion shown in Table 1 could be obtained.

The names and structural formulas of doping molecules (silicon compounds) 1-6 used for silicon doping are shown below.

Doping Molecule 1: Silin

Doping Molecule 2: Tetramethylsilane (SiMe ₄ )

Doping Molecule 3: Tetrakis(methylnitrate)silane (SiPETN)

Doping Molecule 4: Tetrakis(dimethylsilanolyl)silane (Si(SiMe ₂ OH) ₄ )

Doping molecule 5: Tetrakis(trimethylsilyl)silane (Si(SiMe ₃ ) ₄ )

Doping molecule 6: Tetrakis(trimethylsilyl)methane (C(SiMe ₃ ) ₄ )

[0108]

[Diagram 1]

[0109]

[Table 1]

Examples Doping molecule Fraction of doping molecule used in TNT288 molecule Temperature [K](°C) Pressure [GPa] (Si atom/C atom) × 100 (%) 1 Silin 56/288=0.19 3521 (3247.85) 33 3.2 2 SiMe ₄ 60/288=0.21 3525 (3251.85) 34 2,3 3 SiPETN 48/288=0.17 3508 (3234.85) 29 3.1 4 Si( _SiMe2OH ) ₄ 60/288=0.21 3528 (3254.85) 33 32.3 5 Si( _SiMe3 ) ₄ 60/288=0.21 3518 (3244.85) 31 36.0 6 C(SiMe ₃ ) ₄ 60/288=0.21 3518 (3244.85) 30 22.7

[0110]

As follows from Table 1, it is evident that nanodiamonds into which a large number of silicon atoms have been introduced can be obtained in accordance with embodiments of the present invention.

[0111]

Example 7

Using approximately 60 g of an explosive composition obtained by adding 10 parts by weight, 1 part by weight or 0.1 part by weight of triphenylsilanol as a silicon compound to 100 parts by weight of an explosive containing trinitrotoluene (TNT) and cyclotrimethylenetrinitramine (RDX), silicon-doped nanodiamonds were obtained according to a conventional method for producing nanodiamonds. The following treatments were carried out for the obtained silicon-doped nanodiamonds. Note that the added amount of triphenylsilanol to the explosive was 10% by weight, 1% by weight or 0.1% by weight.

(i) Mixed acid treatment

15 g of nanodiamonds obtained through the detonation test were added to 2800 g of a mixed acid consisting of concentrated sulfuric acid and concentrated nitric acid at a ratio of 11:1 (weight ratio), and treated at 150°C for 10 hours with stirring.

(ii) Alkaline treatment

1 g of nanodiamonds treated with mixed acid was added to 100 ml of 8 N aqueous sodium hydroxide solution and treated at 100°C for 10 hours with stirring.

(iii) Annealing

After alkali treatment, nanodiamonds were annealed at a temperature of 800°C in a vacuum atmosphere for 30 minutes.

(iv) Gas phase oxidation

The annealed nanodiamonds were subjected to gas-phase oxidation treatment at a temperature of 300°C in an air atmosphere for 2 hours, thereby obtaining silicon-doped nanodiamonds according to an embodiment of the present invention.

(v) Fluorescence analysis

A 10 wt/vol% aqueous suspension of silicon-doped nanodiamonds according to an embodiment of the present invention obtained by gas-phase oxidation was added dropwise onto a glass substrate and dried, thereby obtaining a sample for evaluation. The obtained sample for evaluation was subjected to high-speed mapping using a confocal Raman microscope spectrometer (trade name: Confocal Raman Microscope LabRAM HR Evolution, available from Horiba, Ltd.), and brightness imaging at a wavelength of 738 nm was performed. Fig. 1(a) shows brightness images at a wavelength of 738 nm of silicon-doped nanodiamonds obtained using triphenylsilanol as a silicon compound in an adding amount, depending on the outer part, of 1 wt%. Fig. 1(b) shows a fluorescence spectrum of the brightness of Fig. 1(a). The zero-phonon line (fluorescence peak) of the silicon vacancy center can be confirmed. The Si content of the obtained silicon-doped nanodiamonds was 3.2% by mass when the added amount of triphenylsilanol in the explosive was 10% by mass, 0.15% by mass when the added amount was 1% by mass, and 0.03% by mass when the added amount was 0.1% by mass.

In Fig. 1(b), it was confirmed that the silicon-doped nanodiamonds according to the embodiment of the present invention have a fluorescence at a wavelength of 738 nm emitted from the center of a silicon vacancy. In addition, the average primary particle size measured by XRD and the specific surface area determined by the BET method of the obtained silicon-doped nanodiamonds are shown in Table 2 below.

[0112]

[Table 2]

Added amount of triphenylsilanol in explosive Specific surface area according to the BET method ( ^m2 /g) Average primary particle size (nm) 10% by weight 213 7.9 1% by weight 232 7.2 0.1% by weight 254 6.9

[0113]

Measurement of specific surface area by the BET method

Device: BELSORP-mini II (available from Microtrac BEL)

Measured amount of powder: 40 mg.

Pre-drying: treatment at 120°C for 3 hours under vacuum.

Measurement temperature: -196°C (liquid nitrogen temperature)

Measurement of average primary particle size (powder X-ray diffractometry (XRD))

Instrument: Multi-purpose X-ray diffraction system with built-in intelligent guidance (available from Rigaku Corporation)

Method for measuring the amount of introduced Si (XRF)

Instrument: ZSX Primus IV X-ray fluorescence spectrometer, available from Rigaku Corporation

The X-ray fluorescence (XRF) measurement results before and after alkali treatment are shown in Table 3, and the XRD measurement results before and after alkali treatment are shown in Fig. 2.

[0114]

[Table 3]

Sample Before processing After processing Mg - 0.02 Al 0.05 0.008 Si 6.3 0.15 P 0.002 0,0005 S 0.24 0.08 Cl 0.03 0.02 K 0.02 0.002 Ca 0.13 0.13 You 0.04 0.04 Cr 0.02 0,010 Fe 0.08 0,050 Ni 0.003 0.002 Cu 0.02 0,009 Zn 0.01 -

*% by weight

[0115]

From Table 3, it can be seen that the amount of Si after alkali treatment measured by XRF was significantly reduced compared with that before alkali treatment, and accordingly, alkali treatment is effective in removing Si.

[0116]

In Fig.2:

A broad peak originating from the amorphous compound was present at about 23°.

Based on the XRF measurement results, except for diamond, the amount of Si was maximum, and thus it is suggested that this peak originated from the Si compound.

Since the broad peak at about 23°C disappeared from the graph after alkali treatment, it is assumed that the Si compound was removed by alkali treatment.

[0117]

Example 8

Nanodiamonds doped with silicon and boron can be obtained by a method similar to that described in Example 7, except for using 0.5 parts by weight of triphenylsilanol and 0.5 parts by weight of phenylboronic acid instead of 1 part by weight of triphenylsilanol of Example 7.

[0118]

Example 9

Nanodiamonds doped with silicon and phosphorus can be obtained by a method similar to that described in Example 7, except for using 0.5 parts by weight of triphenylsilanol and 0.5 parts by weight of triphenylphosphine instead of 1 part by weight of triphenylsilanol of Example 7.

Claims (10)

1. A method for producing a nanodiamond doped with an element of group 14, comprising: alkaline treatment of a nanodiamond composition containing at least one group 14 element selected from the group consisting of Si, Ge, Sn and Pb, and their oxide, and a nanodiamond doped with a group 14 element, with the removal of the group 14 element and its oxide, wherein the group 14 element comprises at least one atom selected from the group consisting of Si, Ge, Sn and Pb. 2. The method according to paragraph 1, including: detonating an explosive composition comprising at least one explosive substance and at least one compound of a group 14 element by explosion in a sealed container to obtain a nanodiamond composition comprising at least one group 14 element selected from the group consisting of Si, Ge, Sn and Pb, and their oxide, and a nanodiamond doped with a group 14 element; and alkaline treatment of the nanodiamond composition with the removal of the group 14 element and its oxide. 3. The method according to claim 2, characterized in that the explosive composition additionally contains a compound containing at least one third element selected from the group consisting of B, P, S, Cr, Al, Li, Na, K, Cs, Mg, Ca, Sr, Ba, Ti, Zr, V, Nb, Ta, Mo, W, Mn, Fe, Ni, Cu, Ag, Zn, Cd, Hg, Ga, In, Tl, As, Sb, Bi, Se, Te, Co, Xe, F, Y and lanthanides. 4. The method according to any one of claims 1-3, further comprising treating the nanodiamond doped with a group 14 element with a mixed acid consisting of concentrated nitric acid and concentrated sulfuric acid, before or after alkaline treatment. 5. The method according to any one of claims 1-4, characterized in that the nanodiamond composition additionally contains at least one third element selected from the group consisting of B, P, S, Cr, Al, Li, Na, K, Cs, Mg, Ca, Sr, Ba, Ti, Zr, V, Nb, Ta, Mo, W, Mn, Fe, Ni, Cu, Ag, Zn, Cd, Hg, Ga, In, Tl, As, Sb, Bi, Se, Te, Co, Xe, F, Y, and lanthanides, and/or its oxide. 6. The method according to any one of paragraphs. 1-5, characterized in that the nanodiamond is additionally doped with at least one third element selected from the group consisting of B, P, S, Cr, Al, Li, Na, K, Cs, Mg, Ca, Sr, Ba, Ti, Zr, V, Nb, Ta, Mo, W, Mn, Fe, Ni, Cu, Ag, Zn, Cd, Hg, Ga, In, Tl, As, Sb, Bi, Se, Te, Co, Xe, F, Y and lanthanides.